SUPERCELLS

B. Put the verbs into the correct simple present tense forms.

SUPERCELLS

Supercells (be)1.   are   rotating updrafts within severe thunderstorms; they (be)2.   are   big, and extremely scary. They can appear anywhere in the world given the right meteorological conditions, but most of the times they (appear) 3. Appear  in the great plains of the US, (last) 4. Last  generally 2-3 hours and they sometimes (split) 5. Split  in 2, with the two resulting storms going in opposite direction. The supercells usually (produce) 6. Produce huge amounts of hail, torrential rainfall, strong winds, and substantial downbursts and they (be)7. are  often carries of giant hail. There are a whole lot of technical details left to be said. Scientists are very interested in supercells , because , as you can guess, they (be) 8. Are   really dangerous.